SoundGuy: AFAIK a pair of Marine G27s or G31s in parallel should have less V drop than a pair of GC2s under high loads. Their design specs include motor starting, so I guess they have more surface area or whatever that deals with that issue. But they usually have less Ah and can't do as many cycles as GC2s.
BFL: 11.2v low cutoff is closer to where the warning should be I think. Mine seems wonky. It doesn't cut-out at 11.6-7V, just starts screaming. Have always backed off then as I don't want to destroy it (ahem!), so I don't know what V it actually cuts off at. Have checked my battery and inverter voltages, and there's little detectable cable (1/0) loss and the lugs are soldered and cool (unlike my previous hammer crimped lugs and #4 cables).
